Ion Battery Materials Research Articles

Theoretical exploration of AlB2 monolayer with high energy storage properties in the field of ion battery materials

The rapid development of electric vehicles has promoted researchers to explore the field of high-capacity batteries. Two-dimensional (2D) materials have been proven to have ultra-high storage capacity due to their unique structural advantages. A first-principles approach was applied here to verify the feasibility of the novel AlB2 monolayer as an anode material with ultra-high storage capacity for Li/Na-ion batteries. The Li capacity of AlB2 monolayer is up to 3308.6 mAh/g. Meanwhile, the Na capacity up to 1654.3 mAh/g. It is worth noting that the diffusion barrier of the monolayer is extremely low (Li: 0.50 eV; Na 0.26 eV). The results show that AlB2 monolayer is a kind of anode material for high energy storage, which provides a new choice for the development of long-life battery.

Bi2S3/rGO nanocomposites with covalent heterojunctions as a high-performance aqueous zinc ion battery material

Bismuth(III) sulfide (Bi2S3) is a promising cathode material for aqueous zinc ion batteries (ZIBs), yet suffers from serious capacity issues due to its poor electrical conductivity and microstructural degradations. In this work, Bi2S3 anchored on reduced graphene oxide (rGO) is prepared through hydrothermal reaction and is used as cathode material for aqueous ZIBs. Raman and XPS characterizations confirmed that the oxygen bridge in Bi–O–C heterostructures is successfully created during the hydrothermal synthesis. These oxygen bridges are energy favourable in the Bi2S3/rGO composite materials and serve as the electron transfer channels for rapid charge compensation during Zn2+ incorporation/extraction. Rotating ring–disc electrode (RRDE) measurements demonstrate improved electrochemical stability of the Bi2S3/rGO composite material compared to pristine Bi2S3. As a result of these improved characteristics, Bi2S3/rGO composite shows notably better rate performance and cycling stability than unsupported Bi2S3. Ex-situ X-ray diffraction and XPS characterizations indicate that Zn2+ undergoes a reversible conversion reaction with Bi2S3 to form ZnS/Bi0, rather than being intercalated into Bi2S3 crystal interlayers. The rGO substrate forms chemical bonds with bismuth in the composite material, and the strongly anchored bismuth on the rGO through a Bi–O–C bridge enables a highly reversible conversion reaction. As a result, the Bi2S3/rGO composite with 8 wt% rGO can deliver a reversible capacity of ∼186 mAh g−1 at the current density of 500 mA g−1 after 150 cycles, showing high promise as Zn-ion battery material.

Effective direct recycling of inhomogeneously aged Li-ion battery cathode active materials

There is growing interest in lithium ion battery materials recycling, and specifically direct recycling, wherein the cathode material is harvested and rejuvenated for use in new batteries. A key risk associated with this process is the fact that materials collected from aged batteries will be inhomogeneous due to the variable experience they incur during use, both between cells and even within cells themselves. In this paper, we investigate the direct recycling process factors that address the effect of three properties of aged and harvested LiNi0.815Co0.15Al0.035O2 (NCA) materials: variation of state-of-charge (SoC), the inconsistent existence of a surface reconstruction layer on the material, and the inhomogeneous growth of the solid electrolyte interface (SEI). We will explore how each property impacts the consistency of the recycled NCA in terms of several key materials properties.

Decoupled alkaline water electrolysis by a K0.5MnO2-Ti mediator via K-ion insertion/extraction.

Conventional one-step water electrolyzers generate H2 accompanied by O2 evolution, and may cause gas mixing and high cell voltage inputs. Herein, using the potassium ion battery material of K0.5MnO2-Ti as a mediator, we effectively decoupled the H2 and O2 evolution of alkaline water electrolysis temporally, thereby achieving a membrane-free pathway for H2 production. As a mediator electrode for charge storage, the K0.5MnO2-Ti exhibited a stable capacity of 100 mA h g-1 at 0.1 A g-1 owing to the reversible K-ion insertion/extraction mechanism. The decoupled water electrolysis device exhibited the step voltages for hydrogen and oxygen production of 1.02 and 0.57 V at 5 mA, respectively. A nearly unity Faradaic efficiency and sustained production of pure H2 has been demonstrated at a constant current density. We anticipate that this mediator demonstrated here may provide a route for the practical application of the decoupling strategy.

(Invited) Electrochemistry Based and Coupled Approaches for Characterization of Lithium Ion Battery Materials and Systems

Lithium ion batteries represent a remarkable technological and commercial success, due to their lightweight and high energy density. However, to address future energy storage needs, there is a need for further research to understand and address lifetime limiting mechanisms. This presentation will highlight progress achieved via electrochemistry based and coupled methods for in-situ and operando characterization of lithium ion battery systems, spanning multiple material chemistries.

Defining Aging Marker Molecules of 1,3‐Propane Sultone for Targeted Identification in Spent LiNi0.6Co0.2Mn0.2O2||AG Cells

Herein we report on an analytical approach for targeted identification of hazardous 1,3‐propane sultone (PS) in spent lithium ion battery material. PS decomposition is investigated with chromatographic techniques coupled to high‐resolution accurate mass spectrometry. Speciation of sulfur‐containing decomposition products is performed and aging marker molecules are defined. The observed PS decomposition results in characteristic 1‐propanesulfonate via electrochemical ring‐opening. Based on this, 1‐propanesulfonate is defined as an ionic marker molecule for electrochemical PS decomposition. Further, volatile methyl and ethyl esters of 1‐propanesulfonate are identified. Their formation is observed mainly caused by elevated temperatures after preceding PS ring‐opening during cell formation. Both, ionic and volatile decomposition markers can be applied for targeted identification of hazardous PS‐containing lithium ion battery material, despite possible consumption of the initial additive molecule.

Resolving the Seeming Contradiction between the Superior Rate Capability of Prussian Blue Analogues and the Extremely Slow Ionic Diffusion.

The superior rate capabilities of metal ion battery materials based on Prussian blue analogues (PBAs) are almost exclusively ascribed to the extremely fast solid-state ionic diffusion, which is possible due to structural voids and spacious three-dimensional channels in PBA structures. We performed a detailed electroanalytical study of alkali ion diffusivities in nanosized cation-rich and cation-poor PBAs obtained as particles or electrodeposited films in both aqueous and non-aqueous media, which resulted in a solid conclusion about the exceptionally slow ionic transport. We show that the impressive rate capability of PBA materials is determined solely by the small size of the primary particles of PBAs, while the apparent diffusion coefficients are 3-5 orders of magnitude lower than those reported in earlier studies. Our finding calls for a reconsideration of the apparent facility of ionic transport in PBA materials and deeper analysis of the charge carrier-host interactions in PBAs.

Electrolytic Recovery of Lithium from Used Li-Ion Battery Material Leachate through a CO2-Negative Process

Lithium materials are attracting attention from industrial and research institutes in recent decades.[1-3] The demand of lithium battery materials is growing due to applications in Li-ion batteries for portable devices, electric-vehicles, and energy storage. In 2016, around 78,000 metric tons of lithium carbonate (equivalent) was consumed, much higher than that in 2010 at 29,000 metric tons, and the statistics forecasted a global demand reaching 509,000 metric tons by the year 2025.[4] Though the increasing consumption of Li2CO3 opens a big market, the producers were still limited, mostly due to high manufacture cost for high purity lithium carbonate. In recent studies, researchers focused on electrolytic extraction of lithium from salt-lake brines and seawater [5, 6], and solvent extraction using organic solvents such as DEHPA/kerosene [7]. These methods were applicable in producing lithium species, but the drawbacks included large amounts of chemical additions and waste generations.In our study, lithium has been electrochemically recovered in a form of Li2CO3, as the last step in separating critical metals from shredded battery materials. This work is part of a larger effort to recover critical elements from Li ion batteries. Other efforts in the project include shredding of used batteries, leaching critical metals from shredded battery materials, and separating Ni and Co from the leachate. The elution from Ni and Co extraction will be used as the anolyte in the electrolytic cell, containing primarily Li and Mn.Aiming at recovering lithium from the elution in a green pathway, we introduced an electrochemical process consuming only the produced Li-rich elution and CO2. In the recovery process, the anolyte was the elution, and the catholyte was a CO2-captured solution. Electrolytic studies were carried out through chronoamperometry and chronopotentiometry measurements. Li2CO3 could be collected as a precipitate product with a 100% purity analyzed with atomic adsorption spectroscopy and X-ray diffraction. After each experiment, the catholyte could be simply recovered by bubbling CO2, and the recovered catholyte has been proved to be effective for multiple uses.The electrochemical method used in this study has been proved to be feasible for the purpose of separating and recovering lithium as a Li ion battery material. In this lithium recovery process, CO2 is captured and solidified. As the only reagent consumed in the process, CO2 can be sourced from air and waste emissions from burning of fossil fuels. Instead of adding additional chemicals such as LiCl [8] and Na2CO3 [9] to catholyte to accelerate lithium extraction and precipitation in literatures, Li ions are directly converted into ultrahigh purity Li2CO3 precipitates in this work.

Usability Identification Framework and High-Throughput Screening of Two-Dimensional Materials in Lithium Ion Batteries.

Two-dimensional materials (2D materials) show great advantages in high-performance lithium ion battery materials due to the inherent ion channels and rich ion sites. Unfortunately, rare 2D materials own all desired attributes to meet complex scenarios. Further enriching the 2D materials database for lithium ion battery use is of high interest. In this work, we extend the list of candidates for lithium ion batteries based on a 2D material identification theory. More importantly, a usability identification framework leveraging the competitive mechanism between the adsorbability and reversibility of ions on a 2D material is proposed to assist the deeper screening of practicable 2D materials. As a result, 215 2D materials including 158 anodes, 21 cathodes, and 36 solid electrolytes are predicted to be practicable for lithium ion battery use. The comparison between the identified 2D materials with the known ones verifies the reliability of our strategy. This work significantly enriches the choices of 2D materials to satisfy the various battery demands and provides a general methodology to assess the usability of unexploited 2D materials for lithium ion batteries.

Coupling Long‐Range Raman with X‐Ray Photoelectron Spectroscopy for Complementary Bulk and Surface Characterization of Battery Materials

AbstractFor the combined surface and bulk characterization of functional powder materials, we report on the direct coupling of Raman spectroscopy with X‐ray photoelectron spectroscopy (XPS) within one setup, avoiding the influence of different sample states and measurement environments. Our approach is based on the Raman integration into the XPS analysis chamber, employing a long‐range camera objective connected to a portable 532 nm Raman spectrometer. For optimization of the measurement geometry, a (400) single crystal (SC), chemical vaper deposition (CVD)‐grown diamond was employed. The applicability of the combined XPS‐Raman spectroscopy approach was first validated by measurements on powder V2O5, used as a commercial standard, and then demonstrated on lithium ion battery materials, that is, LixV2O5 lithium pentoxides. The transferability to other XPS systems is strongly facilitated by the long‐range Raman‐spectroscopic approach, which allowed for Raman analysis over a distance of 320 mm for the CVD‐grown (400) single crystal diamond and 285 mm for LixV2O5. Our results demonstrate the inexpensive and straightforward implementation of coupled XPS‐Raman spectroscopy for combined surface/bulk analysis.

How Li diffusion in spinel Li[Ni1/2Mn3/2]O4 is seen with μ ±SR

Abstract The diffusive behavior in a spinel-type Li+ ion battery material, Li[Ni1/2Mn3/2]O4, has been studied with positive and negative muon spin rotation and relaxation (μ ±SR) measurements in the temperature range between 200 and 400 K using a powder sample. The implanted μ + locates at an interstitial site near O2− ion so as to form a O–H like bond, while the implanted μ − is mainly captured by an oxygen nucleus, resulting in the formation of muonic oxygen. This means that local magnetic environments in Li[Ni1/2Mn3/2]O4 were investigated from the two different sites in the lattice, i.e., one is an interstitial site for μ +SR and the other is an oxygen site for μ −SR. Since both μ +SR and μ −SR detected an increase in the fluctuation rate of a nuclear magnetic field for temperatures above 200 K, the origin of this increase is clearly confirmed as Li diffusion. Assuming a random walk process with the hopping of thermally activated Li+ between a regular Li site and the nearest neighboring vacant octahedral sites, a self-diffusion coefficient of Li+ was found to range above 10−11 cm2/s at temperatures above 250 K with an activation energy of about 0.06 eV.

Investigation of Lithium Ion Diffusion of Graphite Anode by the Galvanostatic Intermittent Titration Technique.

Graphite is used as a state-of-the-art anode in commercial lithium-ion batteries (LIBs) due to its highly reversible lithium-ion storage capability and low electrode potential. However, graphite anodes exhibit sluggish diffusion kinetics for lithium-ion intercalation/deintercalation, thus limiting the rate capability of commercial LIBs. In order to determine the lithium-ion diffusion coefficient of commercial graphite anodes, we employed a galvanostatic intermittent titration technique (GITT) to quantify the quasi-equilibrium open circuit potential and diffusion coefficient as a function of lithium-ion concentration and potential for a commercial graphite electrode. Three plateaus are observed in the quasi-equilibrium open circuit potential curves, which are indicative of a mixed phase upon lithium-ion intercalation/deintercalation. The obtained diffusion coefficients tend to increase with increasing lithium concentration and exhibit an insignificant difference between charge and discharge conditions. This study reveals that the diffusion coefficient of graphite obtained with the GITT (1 × 10−11 cm2/s to 4 × 10−10 cm2/s) is in reasonable agreement with literature values obtained from electrochemical impedance spectroscopy. The GITT is comparatively simple and direct and therefore enables systematic measurements of ion intercalation/deintercalation diffusion coefficients for secondary ion battery materials.

Order and disorder in metal ion battery materials

Order and disorder in metal ion battery materials

An additive-free silicon anode in nanotube morphology as a model lithium ion battery material

Ordered arrays of parallel, cylindrical silicon nanotubes are obtained by aluminothermic reduction of SiO2 nanotubes generated by atomic layer deposition (ALD) on nanoporous aluminum oxide templates. The reduction to amorphous Si (a-Si) is characterized by a combination of X-ray diffraction (XRD), solid-state cross-polarization magic-angle spinning nuclear magnetic resonance (29Si CP-MAS NMR), ultraviolet-visible spectroscopy, attenuated total reflectance infrared spectroscopy (ATR-IR), and X-ray photoelectron spectroscopy (XPS). These a-Si nanotube arrays are electrochemically active in a lithium-ion battery environment when prepared on Cu current collectors without any additives. The absence of the traditional additive carbon black, which is an electrochemically inert conductor, increases the proportion of capacity associated with faradaic reactions (Li incorporation) with respect to the capacitive component. Electrochemical impedance spectroscopy (EIS) and charge-discharge tests demonstrate that the nanotube morphology yields an improved tolerance to fast cycling.

Machine learning of materials design and state prediction for lithium ion batteries

With the widespread use of lithium ion batteries in portable electronics and electric vehicles, further improvements in the performance of lithium ion battery materials and accurate prediction of battery state are of increasing interest to battery researchers. Machine learning, one of the core technologies of artificial intelligence, is rapidly changing many fields with its ability to learn from historical data and solve complex tasks, and it has emerged as a new technique for solving current research problems in the field of lithium ion batteries. This review begins with the introduction of the conceptual framework of machine learning and the general process of its application, then reviews some of the progress made by machine learning in both improving battery materials design and accurate prediction of battery state, and finally points out the current application problems of machine learning and future research directions. It is believed that the use of machine learning will further promote the large-scale application and improvement of lithium-ion batteries.

Picometer scale electron microscopy exploration for the functionality origin of functional materials

The functionality of functional materials originates from field and local symmetry. The local symmetry in matter science is described by four degrees of freedom: Lattice, charge, orbit and spin. To understand and use the rich physical properties brought by the structural distortion of atomic nearest neighbors and second nearest neighbors under symmetry breaking, we need to grasp the fine structure of matter at the picometer scale. This paper reviews the exploration of the origin of functional materials by picometer scale electron microscopy in the three cases in the lattice degree of freedom, the expansion and contraction of the polyhedron, the tilt and rotation of the polyhedron and the cation displacement. In the expansion and contraction of the polyhedron degree of freedom, we use picometer scale scanning transmission electron microscopy (STEM) studies of lithium ion battery materials, which can be classified as the unit cell breathing model and Jahn-Teller effect, to illustrate the relationship between functionalities and structural origins. In the tilt and rotation of the polyhedron degree of freedom, we mainly focus on the heterointerface among functional oxides. The emergent phenomena arising from this heterointerface form most of the topics of modern condensed matter physics, such as high temperature superconductivity, magnetoresistance, antiferromagnetic, multiferroics, etc. Lattice mismatch caused polyhedron tilt and rotation alter the local symmetry of the oxides, and hence various functionalities are created. In terms of cation displacement degree of freedom, ferroelectricity is the typical example to show the structure-property relationship. The most exciting future of ferroelectric material is the potential to be the next generation memory material because of its topological property. With the help of aberration corrected (AC)-STEM, flux closure type and vortex type ferroelectric domain were directly observed at picometer accuracy. Furthermore, through in-situ mechanical and electric force studies, reverse transition from topological and normal ferroelectric state was observed, which paves the way of the application of the ferroelectric material as future memory material system. At the electronic structure level, the charge structure under the picometer-scale lattice structure is reviewed. Through the simultaneously recorded EELS data, we can know the valence state and content fluctuation of certain element. For example, in lithium ion battery materials, atomic and electronic structure changes all the time during the whole working duration. It is crucial to know the local valence state of the transition metal elements. AC-STEM and electron energy loss spectroscopy (EELS) can help us to solve this problem under one time acquisition. And future perspectives of the electron microscopy research on the orbit and spin structure with high spacial resolution are discussed, such as monochromatic EELS, electron-energy-loss magnetic circular dichroism (EMCD), electron-energy-loss magnetic linear dichroism (EMLD) and convergent beam electron diffraction (CBED). CBED is considered to be the best way to discover the orbit structure with high spacial resolution. In terms of spin structure, EMCD and EMLD are not the direct methods to detect the electron spin, which limits the resolution and signal to noise ratio of acquired results. In the future, spin polarized electron source is considered as the proper way to discover the spin structure with high spacial resolution. Nowadays, spacial resolution is not the limit of the TEM. The ability of accessing more kinds of materials, powerful in-situ method and acquiring orbit and spin structure with picometer resolution are goals for us.

Achieving a Zn-ion battery-capacitor hybrid energy storage device with a cycle life of more than 12,000 cycles

Prussian blue is considered as a promising zinc ion battery material because of its advantages such as stable structure, large lattice gap and simple preparation process. However, the poor conductivity seriously hinders the application of Prussian blue electrode materials. Herein we report a simple and interesting strategy to grow Prussian blue nanoparticle on expanded graphite electrode through a facile electrochemical method. Thanks to the synergy between Prussian blue analogue nanoparticles and self-supporting graphite flakes, the composite electrode with unique architectural structure possess both battery and capacitor characteristics. What's even more interesting is that the defects of Prussian blue crystals are gradually reduced during the extraction and insertion of zinc ions, and then the increasingly perfect crystal structure result in excellent cycling performance (120% capacitance retention after 12,000 cycles).

Atomic Scale Insight into Metal Storage and Migration in Novel Anode Materials for Next Generation Battery Technologies

The need for sustainable energy storage and green technology is currently driving the demand for lithium ion batteries (LIBs) to never before seen levels. However, due to the limited Li supply, novel battery technologies are urgently needed. To this end, Li has sought to be replaced by other monovalent metals, such as Na and K, and divalent metals such as Mg, Ca, and Zn. If these battery technologies can be successfully developed, they could make a significant contribution towards meeting the future energy demands. Furthermore, the development of novel LIB electrode materials could potentially increase the current LIB performance. In this work, we have focused on nanoporous carbons for divalent metal ion batteries, and will also compare these to the performance of monovalent metal ions in the same materials. Furthermore, we have investigated bismuth-based anode materials for novel monovalent ion battery materials.1,2 Carbonaceous anode materials have shown promising performance for post-lithium ion batteries such as sodium ion batteries (NIBs), and potassium ion batteries (KIBs), but are also starting to be explored for divalent ion battery technologies.3–5 These carbonaceous anode materials commonly consist of sp2-hybridized carbon sheets with a plethora of defects. Hence, we in this study investigate the fundamental influence of defects in graphene on the energy storage mechanism, and their implication on the battery performance of Mg, Ca, and Zn ion batteries.5 Through density functional theory calculations, it was found that pristine graphene does not provide suitable metal storage sites for either Mg or Zn, whereas the calculated metal adsorption energies suggest that Na, K, and Ca may be readily adsorbed and stored on pristine graphene, even though adsorption energies similar to those calculated for Li on graphene were not obtained for any of these metals. The inclusion of defects on the graphene sheet, especially O- and N-heteroatom defects, lead to an increase in metal binding energies, suggesting that these defects could be used to boost the metal storage potential, showing a direct link between electrode structure with electrochemical performance. One caveat with metal storage on defect sites is the risk of capacity loss between the initial and subsequent charge/discharge cycles due to strong binding between metals and defect sites. Calculations of metal migration energies showed that the weak interaction between zinc and the carbon systems lead to rapid diffusion, but would not necessarily make these systems suitable as zinc ion battery electrodes. The only defect that would lead to irreversible capacity for the Ca and Mg ion batteries is the NC2OC defect, with calculated metal migration barriers of >0.5 eV. This defect was also found to be detrimental to Na and K diffusion. In summary, heteroatom defects were shown to be beneficial for anode performance, but the exact structure of the defect is important as not to trap metal ions irreversibly.Finally, we also investigated bismuth-based electrode materials, both alloying with Li, Na, and K, and novel LIB intercalation-type anodes (Bi2S3 and Bi2MoO6). These materials were shown to have energetically favourable Li intercalation, and the potential to form different Li, Na, and K intermetallic alloys depending on metal loading during charge/discharge, making them promising next generation battery technologies.AcknowledgmentThe financial support from EPSRC (Engineering and Physical Sciences Council) under the grant number EP/M027066/1, and EP/R021554/2, is acknowledged.References 1 J. Bai, X. Chen, E. Olsson, H. Wu, S. Wang, Q. Cai, and C. Feng, J. Mater. Sci. Technol. (2020). 2 T. Zhang, E. Olsson, M. Choolaei, V. Stolojan, C. Feng, H. Wu, S. Wang, and Q. Cai, Materials (Basel). 13, 1132 (2020). 3 E. Olsson, J. Cottom, H. Au, Z. Guo, A.C.S. Jensen, H. Alptekin, A.J. Drew, M.-M. Titirici, and Q. Cai, Adv. Funct. Mater. 1908209 (2020). 4 E. Olsson, G. Chai, M. Dove, and Q. Cai, Nanoscale 11, 5274 (2019). 5 E. Olsson, T. Hussain, A. Karton, and Q. Cai, Carbon N. Y. 163, 276 (2020).

(Invited) Cation-Disordered Li3VO4-Based Materials As a Pseudocapacitive Negative Electrode

The growing demand for fast charge-discharge electrical energy storage (EES) devices with long cycles lifetimes has led to the need for alternatives to current battery systems, which store energy via slow faradic reactions. Among different EES technologies, electric double layer capacitors (EDLCs) are considered as promising devices due to their high-power, safe and long-lived characteristics. One of the approaches to further enhance the cell voltage and energy density of EDLCs while maintaining their high power is to replace the activated carbon with ultrafast lithium ion battery materials as hybrid supercapacitors.The orthorhombic β-Li3VO4 (β-LVO) has been identified as a promising negative electrode material for hybrid supercapacitors, with theoretical specific capacity of 394 mAh g-1 (2 lithium accommodation)[1]. The electron-donor effect of Li, exactly opposite to the inductive effect of polyanions, lowers the redox potentials of V5+/V4+ and V4+/V3+ to a safe but still low potential range between 1.3 and 0.4 V vs. Li/Li+, compared to the 3.0 V usually observed for V2O5. Recent our studies [1-2] unveiled that both the structure and electrochemical signature change of the β-LVO during the initial cycling, resulting in what we termed as electrochemical activation process. This electrochemical activation process induces the transformation of β-LVO from the pristine cation-ordered structure into an activated LVO, which has a Li+/V5+ cation-disordered structure. Charge discharge curves also change from “battery-like” plateau to “pseudocapacitive” slope via such cation-disordering of LVO, along with its reaction mechanism change from two-phase to solid-solution reaction[2]. Li+ diffusion coefficient (DLi ) evaluation by galvanostatic intermittent titration technique (GITT) reveals that the DLi of cation-disordered LVO is two orders of magnitude higher than the one of pristine β-LVO. Yet, the preparation method of cation-disordered LVO has been a major issue as the electrochemical activation process of β-LVO is impractical from the industrial point of view. Such electrochemical process requires a precycling of β-LVO for 10-20 cycles down to low potential below 0.4 V vs. Li/Li+, which is difficult to control and inevitably produces undesirable irreversible capacity for a full cell assembling.In this talk, we introduce an alternative to the electrochemical process, i.e., the direct synthesis of fully cation-disordered LVO via simple mechanical milling of the pristine β-LVO powder (Fig.1). The mechanochemical process brings about the disordering of LVO cation sublattice and thus enables to obtain thermodynamically metastable cation-disordered LVO phase without any precycling. Comparison of X-ray and neutron powder diffraction patterns confirmed the successful direct synthesis of cation-disordered LVO. The mechanochemically cation-disordered LVO shows superior rate performances to those of β-LVO and even electrochemically cation-disordered LVO. Another strategy to synthesize pseudocapacitive LVO-based material is a partial substitution of V5+ with Si4+ in β-LVO, which results in a transformation into γ-Li3+xV1-xSixO4. The γ-Li3+xV1-xSixO4 , with a partially V5+/Si4+ cation-disordered structure shows similar psuedocapacitive behavior as a fully cation-disordered LVO with enhanced DLi and rate capability compared to the β-LVO, thanks to the randomly distribution of V5+. In the presentation, we introduce those two approaches, “fully” or “partially” cation-disordering, as new paths for transformation of battery into pseudocapacitive materials with improved electrochemical performances by simple cation mixing.

Preliminary Study of Synthesis of Sodium Manganese Oxide Using Sol-Gel Method as Sodium Ion Battery Material

Sodium ion battery is one of the promising alternatives to lithium ion battery. Sodium manganese oxide as the sodium ion battery catode material has been synthesized by modifying the sol-gel method used to obtain lithium manganese oxide. The precursors used were table salt and manganese chloride. The sol-gel process used was water solvent, citric acid as a chelating agent and chitosan as the template. Thermal decomposition and formation zone obtained from simple thermal analysis using furnace and digital scales. Calcination was carried out at 600°C and 850°C for 2 hours. Crystal properties and morphology were analyzed using XRD and SEM. Based on the analysis of XRD pattern, sodium manganese oxide crystals (Na0.7MnO2.05 JCPDS 27-0751) have been formed at both of the calcination temperature. Observed morphology of the sample showed the domination Mn3O4 JCPDS 18-0803 in accordance with crystalline phase identification. These results demonstrate that the modified sol-gel method could be used to obtain sodium manganese oxide as sodium ion battery cathode material.